This invention relates to a vacuum fixation bag and method of use thereof The. invention as described relates to a sterile vacuum fixation bag for use in stabilizing the head during medical and surgical procedures where the head must remain immobilized for prolonged periods of time. The device provides for semi-rigid fixation of the head within the setting of medical imaging studies including but not limited to computed tomography (CT), magnetic resonance imaging (MRI) studies, nuclear medicine studies and positron emission tomography (PET). The invention described is also suited for use during invasive procedures that require head fixation such as neurosurgical procedures, ophthalmologic procedures, cranio-facial surgery and other procedures involving the head and face that require head immobilization. The invention is designed for placement inside of standard imaging systems such as the head coil of an MRI scanner or the head platform of a CT scanner. The invention is suitable for head stabilization during cranio-facial procedures, neurosurgical procedures, opthomolgical procedures and any type of procedure requiring head immobilization by attachment to the operating or procedure table.
The current practice of medical imaging relies upon the acquisition of multiple images during the routine sequence of imaging a single subject. Often the acquisition of the serial images is compromised by patients moving their head during the imaging acquisition period. It is estimated that 30% of medical imaging, specifically, magnetic resonance imaging studies, need to be repeated due to head motion artifact. Additionally, newer imaging modalities rely on the reproducible location of sequential images to provide localizing information during studies such as functional MR imaging. The movement of subjects during such studies invalidates the data obtained and necessitates the reimaging of said individuals. The invention submitted addresses this problem by providing a non-invasive sterile device for semi-rigid head fixation during medical imaging procedures. The device is a single use, sterile vacuum fixation bag specifically designed to address the problem of patient movement during medical imaging. The invention is designed to fix the subject""s head within the medical imaging device and provide semi-rigid fixation during the imaging procedure to reduce the need to repeat the imaging due to patient head movement.
The invention submitted also provides for semi rigid head fixation during medical procedures that require head fixation. The indications for usage would include any procedure where head immobilization is sought to either facilitate the procedure or protect the patient""s head during the procedure. Current indications would include but not be limited to any type of craniofacial procedure including neurosurgical, ophthalmologic, otolaryngology, radiologic, dental or plastic surgery procedure where head stabilization is desired. The invention submitted provides for semi-rigid fixation by application to the subject""s head and attachment of the device to the operating or procedure table. The invention is non-invasive and provides head fixation during procedures that require head immobilization.
The invention submitted is a single use, sterile vacuum fixation device for stabilization of the head during medical imaging or surgical procedures. The invention is a vacuum fixation device comprised of an airtight plastic bag which contains Styrofoam beads and a closable port for insertion and withdrawal of air. The unique configuration of the bag allows for semi rigid fixation of the head by providing contact along the under surface of the mandible, the lateral portion of the head bilaterally to contact the peri-auricular surfaces and a forehead portion configured for contacting the subject""s forehead. The invention is also provided in a form that allows for access to the cranial vault for cranial procedures. Once fitted to the subject, air is evacuated from the bag via the closable port bringing the Styrofoam beads into close proximity to one another developing the semi rigid mold which provides the basis for the semi-rigid fixation. The device is then fixed to either the medical imaging device or the procedure table to secure the subjects head.
The vacuum fixation bag is made by methods well known in the art. The bag is made of a plastic material, such as any flexible plastic that is suitable for external use in a medical device. The foam beads can be made of any suitable multicellular expanded synthetic resinous material, such as Styrofoam. The closable stem is likewise made of flexible plastic which is melded to the bag to provide a passage for air into and out of the bag. The closable stem has a stopper at its distal end which can be opened to release air or inserted to prevent air from entering the system.
The application describes a head immobilization device that has a unique geometric configuration that addresses several issues unique to this patent application. Firstly, the device is configured to allow for semi-rigid fixation of the head using polymer beads contained within thin plastic sheeting. Rose, et al (U.S. Pat. No. 3,745,998) discuss vacuum immobilization and note xe2x80x9cnumerous evacuated envelopes have been proposed for use as rigidified immobilization devicesxe2x80x9d [Section 14, line 48]. Rose continues in their application to define more specifically the nature of the elastic materials and the filler; however in contrast to the current application, Rose only provides for very simple designs which are useful only during immobilization of a single extremity or of the body as a whole. The issues involved in immobilization of the head are not addressed in any fashion and the invention as described would not provide for adequate immobilization of the head. Adequate immobilization of the head requires specific points of contact to limit motion in flexion, extension, rotation, and lateral movement. Thus, while the general use of a vacuum immobilization device is presented by Rose, et al. the utility of this device for immobilization of the head is not feasible and not inferred in their application. The submitted invention provides a unique geometric design exclusively provided for immobilization of the head utilizing a well known technique which incorporates vacuum fixation.
Secondly, it is provided that Chitwood, et al. (U.S. Pat. No. 5,454,781) provides for a device used to provide cervical traction. The device only provides contact with the subject""s neck area and a forehead strap is provided to further restrain the subject. The device provides for cervical traction/stretch and is not designed for immobilization. This device, as described, fails to provide fixation of the head in such a fashion as to prevent movement. The subject would be able to move their head in several directions since the device only provides fixation about the neck and forehead. Lateral movement of the head is not addressed nor is flexion/extension. Chitwood, et al. provides a continuation of U.S. Pat. No. 5,441,479 in their U.S. Pat. No. 5,569,175. U.S. Pat. No. 5,569,175 was also provided as evidence of prior art. Chitwood, et al again describe a continuation of their earlier work now providing a platform for attaching the cervical traction device. Again, this invention in not designed for head immobilization and to the contrary, is designed for xe2x80x9crotation of the platform about any one of or all of an x-axis, a y-axis, and a z-axisxe2x80x9d [Section 2, line 10-11]. Chitwood, et al. fail to describe a device that is intended for head immobilization and to the contrary describe a device that promotes movement of the head while producing traction of the neck. The current invention submitted (Ser. No. 10/084,953) does not produce traction of the neck since this effect would be deleterious in many patient/subject populations for which the device is intended. Cervical traction is utilized in very specific medical conditions and its general application can be unsafe; additionally, is not the standard of care to use cervical traction for head immobilization.
Three additional patents are provided as references. Gottfried, et al., U.S. Pat. No. 3,397,688 provides for a pneumatic head and neck immobilizer. The device discussed by Gottfried provides immobilization by inflating a device around a subject""s head and securing the device under the armpits. The device fails to provide a similar utility as the submitted invention for several reasons. First, the device by Gottfried does not allow access to the head or the auditory canal a feature which is critical for use during medical procedures. Secondly, the device fails to adequately define the degree of immobilization as no portion of the device resides under the chin of the subject; thus flexion and lateral movements are possible with this system. Thirdly, the invention by Gottfried, et al. is likely to produce some degree of downward axial traction on the cervical spine as it is designed, a feature which is not desirable in the context of patient care. Lastly, the device is too large and cumbersome to fit within modern imaging devices. Additionally, the device functions by inflation and could damage delicate imaging equipment such as an MRI head coil. It is therefore provided that the invention of Gottfried, et al. has no relationship to the proposed invention.
Fogelberg et al., U.S. Pat. No. 6,079,056, provide a device for air cushioning during sports. The device has no bearing on the current invention submission. Fogelberg""s device is for prevention of sporting injuries and would not provide any support of the head nor would the device reduce head movement in any fashion. The construct of this invention is to go around the head and provide impact protection to the shoulders, clavicles and scapular areas. Additionally, the materials of construction are different than the submitted invention and would not be feasible for use in the current application.
Hayes, et al. U.S. Pat. No. 4,885,811, provides a device for protection of bodies during transport. The invention of Hayes discusses a vacuum fixation mold which provides for immobilization of the entire body between two sheets. The device does not provide for head immobilization as such and would not allow access to the face, auditory canals, or cranial vault. The invention of Hayes does not provide specific design characteristics which provide for head immobilization, nor does the device size allow for its use in medical imaging equipment or during other medical procedures. Thus, while the general use of a vacuum immobilization device is presented by Hayes, et al. the utility of this device for immobilization of the head is not feasible and not inferred in their application. The submitted invention provides a unique geometric design exclusively provided for immobilization of the head utilizing a well known technique which incorporates vacuum fixation.
It is therefore proposed that the current application is distinctly different from the other applications provided as proof of the current art. The invention xe2x80x9cVacuum fixation bag for stabilizing the headxe2x80x9d is a unique concept specifically designed to address the unique problems of head fixation. While the utilization of vacuum fixation has been used by many others, the specific geometric design and medical applications of this invention have not been proposed or inferred in other patents.
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The invention relates to a vacuum fixation device and method of use thereof with applications for, but not limited to, head stabilization during medical imaging and surgical procedures. The first application of the invention is in the field of medical imaging. Newer imaging techniques such as magnetic resonance imaging, computed tomography, and nuclear imaging studies are obtained by acquiring repeated images of the head over time. Some of these procedures can last for long periods of time and require of subjects long periods of movement restriction. Under current imaging conditions, it is difficult for even the most compliant subjects to remain motionless for extended periods of time. Movement that occurs during medical imaging causes multiple problems including degradation of imaging quality, difficulty with image alignment and most importantly these limitations often necessitate repetition of imaging cycles to obtain artifact free imaging. More sophisticated imaging techniques such as functional magnetic resonance imaging requires multiple images, obtained over long periods, to be overlaid on one another to evaluate signal characteristics within single image voxels over time. Head movement during such procedures make temporal analysis of regions of interest difficult if not fully unreliable. The invention submitted allows for movement restriction during these types of medical imaging procedures by providing semi-rigid head fixation within the imaging device.
It is difficult for motivated subjects to remain motionless during these imaging procedures but it is even more difficult to image noncompliant subjects. Specific examples would include children and subjects with learning disabilities or comprehension deficits. These subjects often present a marked challenge to acquiring adequate, motion-free images due to their inability to remain motionless during imaging. These subjects often must be sedated with medication prior to undergoing imaging and because of this necessity these subjects endure the risks associated with anesthesia and sedation. The invention submitted is suitable for use during imaging of non-compliant subjects and will reduce the necessity to sedate these subjects during medical imaging.
Many devices have been developed to address the issue of head movement during medical imaging. These devices have included solid bite bars and plastic molds of the subject""s face. These devices have provided poor results and are not suitable for the majority of subjects who undergo medical imaging. One specific example relates to the use of these devices in patients with seizure disorders or in subjects who have any risk of developing seizure activity such as head trauma patients. Rigid fixation within the scanning environment is not safe because of concerns regarding trauma during a seizure directly from the device or the compromise of a subject""s airway during a seizure event. The current invention provides a safe method to restrain the subject""s head without compromising safety or airway access. The current invention is semi-rigid and will deform if sufficient force is applied as when a seizure event occurs. Additionally, the current invention provides head restraint without covering the face or airway thus providing freedom from airway obstruction and access to the subject""s face if needed in a medical emergency.
The current state of head stabilization in the majority of imaging centers worldwide is to use strips of foam padding and surgical tape to secure the subject""s head within the imaging device. This procedure is time consuming, provides little head stabilization, and is non-hygienic. The current invention provides for efficient, hygienic, comfortable head stabilization without the risks associated with rigid head fixation.
The economic impact of being able to image subjects without head movement is an important aspect to the utility of this invention. Routine medical imaging is a multi-billion dollar segment of the health services industry and a major portion of the gross domestic product of the United States. Billions of dollars from private, corporate, insurance, and governmental agencies are spent each year on medical imaging. These costs could be reduced if medical imaging procedures were obtained on the initial attempt without the need to repeat a portion of the procedure. If fewer studies needed to be repeated, then the productivity of imaging centers would increase and patient access to these resources would increase as well.
A second indication of the current invention is to provide head stabilization during medical procedures. Many fields of medicine provide care for the upper portion of the body including the regions of the head and face. Many invasive and non-invasive procedures performed on the head and face require that the head and neck be immobilized during the time the procedure or surgery takes place. Inclusive in this arena is the application of intra-operative imaging techniques whether frameless or frame dependent technology and other types of imaging studies including but not limited to cerebral angiography. It is established that head fixation is necessary in most neurosurgical and craniofacial procedures. This fixation is currently obtained using rigid, invasive head fixation, for example using a Mayfield head holder, which uses skull pins to clamp the subject""s head rigidly to a frame which is secondarily attached to the operative table. Many neurosurgical and craniofacial procedures do not require such rigid fixation and semi-rigid fixation would be more appropriate while still providing for patient safety and surgeon comfort and access. Examples include but would not be limited to brain biopsies, awake craniotomy procedures, smaller neurosurgical cases such as ventricular peritoneal shunt placements or revisions and a variety of craniofacial and neurosurgical procedures performed on children. Many traumatic injuries also can be managed with semi rigid vs. rigid fixation. Additional uses would include but not be limited to functional neurosurgical procedures where stereotactic localization is performed to obtain biopsy coordinates or localization for placement of neuro-implants.
The current invention will provide stabilization in four critical locations including the forehead, ears, chin and jaw, yet the entire face remains exposed as to provide access for anesthesia and surgical operations in that area. The cranial vault is likewise exposed and available for any variety of cranial procedures. While the device allows for semi-rigid fixation and access to the face and cranial vault, the invention eliminates several risks associated with rigid fixation including skull fractures, extra and intracranial bleeding from skull pin application, and the risk of superficial and deep infections that result from skull pin placement using devices such as the Mayfield head holder.
The invention is provided as a single use, sterile item and would alleviate the necessity to sterilize the item prior to usage. This promotes rapid operative and procedure room turn over making the medical institution more productive and cost efficient.
In view of the foregoing, it will be appreciated that providing a vacuum fixation device for use in medical imaging and medical procedures/surgery that is hygienic, inexpensive, comfortable, and immobilizes the head at critical points of contact including the forehead, ears, chin, and jaw while providing access to the face and cranial vault would be a significant advancement in the art.
The current invention submitted is a vacuum fixation device designed to provide semi-rigid head fixation during medical imaging and medical procedures/operations of the face and head. The invention is a vacuum fixation bag that is designed to provide contact with the subject""s head creating semi-rigid immobilization. The invention is comprised of an airtight flexible bag containing an effective amount of Styrofoam beads and a closable port configured for passage of air into and out of the bag such that when air is evacuated from the bag, the beads conform to the head providing semi-rigid fixation. The bag is especially configured to provide stabilization to the neck, the under surface of the mandible, the lateral head around the peri-auricular surfaces, and the forehead. The configuration of the invention provides full access to the subject""s face and cranial vault while providing access to the auditory canals, a feature which is desired during medical imaging studies where communication with the subject is desired or during surgery where the patient is awake.
The current invention is provided as a sterile, single use item that provides semi-rigid head fixation in an inexpensive, comfortable format during medical imaging procedures and during medical procedures/surgery involving the face and/or head.
An invention is detailed for stabilizing a subject""s head during medical imaging procedures and during medical procedures/surgery involving the face and/or head comprising:
a) a vacuum fixation device comprised of an airtight flexible bag containing an effective amount of beads, the bag comprising a neck-ring portion configured for mandible fixation, a lateral head portion configured for contacting peri-auricular surfaces of the subject""s head, a forehead portion configured for contacting the subject""s forehead, and a closable port for passage of air into and out of the bag;
b) stabilizing the inferior aspect of the mandible with the neck ring portion, stabilizing and fixing the subject""s periauricular cranium with the lateral head portion, and the subjects"" forehead with the forehead portion of the vacuum bag; and
c) evacuating air from the vacuum fixation bag such that the vacuum fixation bag and beads conform to the subject""s head, thereby forming a semi-rigid cast whereby the head can be fixed either within the medical imaging device or to the operating/procedure table during procedures involving the face or head.
d) The vacuum fixation bag fixes the head at four critical axes of potential movement (mandible and forehead [out-of-plane movement], and bilateral peri-auricular surfaces [in-plane movement]).
e) The configuration of the device provides semi-rigid fixation but allows access to the entire face and cranial vault
f) The device is semi-rigid but deformable under adequate stress providing a safe mechanism to restrain non-compliant subjects such as children or those with mental capacity that limits their ability to comply during imaging procedures/medical procedures.